Closure device for closing an entrance opening



April 25, 1967 K. S. R. HULTGREN CLOSURE DEVICE FOR CLOSING AN ENTRANCE OPENING Filed Mrch 12, 1965 INVENTOR KARL STEN RUDOLF HULTGAEN AT-roraua':

United States Patent.

3,315,412 CLOSURE DEVICE FOR CLOSING AN ENTRANCE OPENING Karl Sten Rudolf Hultgren, Bofors, Sweden, assignor to Aktiebolaget Bofors, Bofors, Sweden, a Swedish corporation Filed Mar. 12, 1965, Ser. No. 439,382

Claims priority, application Sweden, Mar. 20, 1964,

3,526/64 4 Claims. (Cl. 49-246) The present invention relates to a closure device, and particularly to a door for an entrance port or a manhole of a motorized artillery gun or similar device.

Doors for entrance ports or manholes of movable guns and similar devices, in order to protect satisfactorily personnel present within the space closed off by the door, should have a considerable weight whereby the handling of such doors is often laborious. In particular if the door, which is often desirable, is to be arranged in a substantially horizontal wall, it is often necessary in devices as now known for hinging such doors to have a hoisting apparatus especially for the purpose of moving the door from its closed into its open position, and vice versa.

The present invention provides a device for hinging a door for a port, as for instance, a port for personnel entering or leaving, by means of which the opening and the closing of the door is facilitated in that the door, when being moved from the closed to the open position and vice versa, is subjected to compensatory forces which are produced by said device and substantially counteract the strong gravitational forces acting upon the door due to its weight. The device of the invention is so arranged that the door, while being moved into its open or closed position, continuously occupies a position substantially parallel to the wall surrounding the port.

For this purpose the door is, according to the invention, hinged to the wall by means of two parallel lever linkages, each comprising at least two pivotal levers. The parallel lever linkages are arranged on each one side of the door and pivot in mutually parallel planes, one end of each one of the levers being secured to the wall and the other end to the door by means of pivotal joints, one at each end of each lever. At least one of said pivotal joints by means of which the levers are attached to the door pivotal in bearings secured thereto, comprises a pivot secured to the lever and extending perpendicularly to the planes in which the levers pivot. The pivot is further fastened to a torsion rod secured against rotation, the other end of the rod being fastened to the door, also secured against rotation.

In a preferred embodiment according to the invention the door is hinged in four levers forming two parallel lever linkages in which the door end of each pivotal lever is secured as described by means of a pivot shaft to a torsion rod, the other end of which is secured to the door.

With this device for swinging the door to or from the open or closed position, respectively, it is convenient to provide an arrangement of locking means for holding the door in either of said two positions or in intermediate selected position, which does not require any components of the locking means mounted on the wall area surrounding the port so that this wall area can be left free of such components. To attain the purpose, at least one pivotal lever, preferably, however, one pivotal lever of each parallel lever linkage, comprises abutment means located at a distance from the pivot thereof attached to the door, and the door comprises displaceable locking members to cooperate with said abutment means.

The invention will be further explained by the following description of a preferred embodiment thereof as shown in the accompanying drawings, in which:

FIG. 1 shows a door according to the invention, illus- 3,3 15,4 12 Patented Apr. 25, 1 967 trated in closed position covering a port or manhole in a wall to which the door is hinged;

FIG. 2 shows the door in a stage of an opening movement from the position illustrated in FIG. 1;

FIG. 3 shows locking means for locking the door in a selected one of several positions; and

FIG. 4 illustrates the means for locking the door in different positions.

As illustrated, a wall 1 includes a manhole or port 2 to be closed by a door in the form of a heavy closure plate 3, which, in closing position, covers the port 2 as shown in FIG. 1. The door is attached to the wall 1 by means of four pivotal levers 4, 4 and 5, 5, each being at one end attached to the wall 1 by a pivotal joint 6, 6' and 7, 7, respectively, and to the door by a pivotal joint 8, 8' and 9, 9', respectively. The pivotal levers 4 and 5 on one side and 4' and 5' on the other mutually consti tute parallel lever linkages whereby the door, when being swung outwards or inwards in relation to the wall, moves in substantially parallel planes during the pivoting of the pivotal levers. Obviously, the pivotal levers 4, 4' and 5, 5, respectively, of the lever linkage here referred to as parallel lever linkages need not necessarily to have the same length. If it be desired that the angle between the plane of the wall surrounding the port and the plane of the closed door changes during the swinging of the door, the levers of the pairs may have lengths different one from another, the motions of the door then being a combination of parallel and tilted displacements.

In the embodiment as illustrated, the lever ends at the door are fastened to one end of a torsion rod or bar 10, 10', 11 and 11, respectively. At that end, each torsion rod may constitute a mounting shaft for the pertaining lever, or it may be secured to a lever pivot journaled in bearing blocks 18, 18', 19, 19', respectively, so that the rod is loaded when the respective lever is pivoted. Each torsion rod is, at its other end, secured to the door by means of splines 15 inserted in correspondingly splined bores 16 of the bearing blocks 18, 18, 19, 19.

With a door hinged by means of lever linkages of the kind described, it is possible, by suitably dimensioning the torsion rods, to attain that the weight of a door which during the entire swinging movement occupies a substantially horizontal position is substantially counteracted by a force acting at the ends of the pivotal levers and caused by the torsional momentum developed in the torsion rods. If the torsion rods are so arranged that they do not develop a torsional force in a position of balance of the pivotal levers in which the same are substantially normal to the wall 1, the momentum of the force of gravity tending to turn the levers about the pivotal joints 6, 6', 7, 7 will for all other positions of the door be substantially counteracted by the force originating from the torsional momentum of the then loaded torsion rods. Accordingly, the force required for swinging the door in either direction can be substantially compensated by properly dimensioned torsion rods. As it is obvious, the gravity force acting as a turning force at the joints attached to the wall 1 will vary during the movement of the door away from and toward the balance position according to the sine of the angle between the pivotal levers and the vertical, and the torsion force is substantially proportional to the same angle. Accordingly, a full compensation of the weight cannot be readily obtained for all positions of the door. However, by suitably selecting the dimensioning of the torsion rods, the force necessary for moving the door to swing the door from either end position thereof can be made very small in relation to the weight of the door.

The length of the pivotal levers, in particular of the pivotal lever 5 and 5', must be so selected that the port 2 is fully accessible. To this end, the pivotal levers 5 and should be at least half as long as the length of the door in the direction of pivoting of the levers. If the Wall at the side of the door towards which the door opens is at an angle to the wall surrounding the port and it is desired that the door, when in open position, is located tightly adjacent the wall, the pivotal levers 4, 4 may, as mentioned above, have lengths different from those of the pivotal levers 5 and 5'.

The invention relates also to means for locking the.

door. As can best be seen in FIGS. 3 and 4, these means preferably are arranged so that the door can be locked in a number of different positions. For this purpose, the pivotal levers of plates 22 and 22 including holes 20, 21 and 20, 21', respectively. The plates are fastened to levers 5 and 5 respectively, at the ends thereof at the door 3. The holes 20, 20' and 21, 21', respectively, coact with displaceable locking members movable in guides in the door. The locking means are shown as bolts 23 and 23, respectively, which by means of connecting rods 24, 24', respectively, and a pivotal lock handle 25 can be moved into engagement with holes 2i) and 20 or 21, 21, respectively depending upon the position of the door.

While the invention has been described in detail with respect to certain now preferred examples and embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended to cover all such changes and modifications in the appended claims.

What is claimed is:

1. A closure device for closing an entrance opening in a wall, said closure device comprising a closure plate for closing said wall opening, a pair of parallel linkage means, each of said linkage means including at least two levers disposed on two opposite sides of said closure plate, a first mounting means for pivotally securing one end of both levers of each linkage means to said wall, a pivotal second mounting means securing the other end of both levers of said linkage means to the closure plate, the levers of both linkage means being pivotal in mutually parallel planes for lifting and lowering said closure plate in reference to the wall, a torsion member for each of said levers, each of said torsion members being secured at one end to the closure plate and at the other end to the respective second mounting means for distorting said other end in'reference to said respective lever, the resulting members generating torsional distortions of the torsion forces counteracting the 5 and 5 mount receiving means in the form the levers of said linkage means one end by pivoting the gravitational force acting upon the closure plate when the same is lifted or lowered in reference to said wall, locking means on said closure plate and said pivotal second mounting means for locking the latter in a predetermined pivotal position in reference to said closure plate, said locking means including a locking member movably supported by said closure plate and a receiving means on said second mounting means, and an actuating member coacting with said locking member for moving the latter into and out of engagement with said receiving means, said receiving means including a locking plate including several locking holes and supported by said second mounting means pivotal in unison therewith in response to a pivotal movement of the respective lever, engagement of said locking member with a selected one of said holes locking the levers in corresponding angular positions in reference to the closure plate.

2. A closure device according to claim 1, wherein each of said torsion members comprises a torsion bar disposed normal to said parallel planes, one end of each bar being fastened to the closure plate secured against rotation in reference thereto, and the other end being secured to said pivotal second mounting means for angular turning of said other end in reference to said one end in response to a pivotal movement of the respective lever, thereby causing said distortions of the torsion members.

3. A closure device according to claim 1, wherein each of said torsion members is in a substantially torsion-free state when said closure plate is lifted into its substantially uppermost position in reference to the wall by pivoting in the direction for lifting the closure plate.

4. A closure device according to claim 1, wherein a locking means is provided for each of said second mounting means, and wherein said actuating member is connected to the locking member of each locking means to move both said locking members into and out of locking engagement.

References Cited by the Examiner Gutowski et a1. 49-379 HARRISON R. MOSELEY, Primary Examiner. KENNETH DOWNEY. Examiner. 

1. A CLOSURE DEVICE FOR CLOSING AN ENTRANCE OPENING IN A WALL, SAID CLOSURE DEVICE COMPRISING A CLOSURE PLATE FOR CLOSING SAID WALL OPENING, A PAIR OF PARALLEL LINKAGE MEANS, EACH OF SAID LINKAGE MEANS INCLUDING AT LEAST TWO LEVERS DISPOSED ON TWO OPPOSITE SIDES OF SAID CLOSURE PLATE, A FIRST MOUNTING MEANS FOR PIVOTALLY SECURING ONE END OF BOTH LEVERS OF EACH LINKAGE MEANS TO SAID WALL, A PIVOTAL SECOND MOUNTING MEANS SECURING THE OTHER END OF BOTH LEVERS OF SAID LINKAGE MEANS TO THE CLOSURE PLATE, THE LEVERS OF BOTH LINKAGE MEANS BEING PIVOTAL IN MUTUALLY PARALLEL PLANES FOR LIFTING AND LOWERING SAID CLOSURE PLATE IN REFERENCE TO THE WALL, A TORSION MEMBER FOR EACH OF SAID LEVERS, EACH OF SAID TORSION MEMBERS BEING SECURED AT ONE END TO THE CLOSURE PLATE AND AT THE OTHER END TO THE RESPECTIVE SECOND MOUNTING MEANS FOR DISTORTING SAID OTHER END IN REFERENCE TO SAID ONE END BY PIVOTING THE RESPECTIVE LEVER, THE RESULTING DISTORTIONS OF THE TORSION MEMBERS GENERATING TORSIONAL FORCES COUNTERACTING THE GRAVITATIONAL FORCE ACTING UPON THE CLOSURE PLATE WHEN THE SAME IS LIFTED OR LOWERED IN REFERENCE TO SAID WALL, LOCKING MEANS ON SAID CLOSURE PLATE AND SAID PIVOTAL SECOND MOUNTING MEANS FOR LOCKING THE LATTER IN A PREDETERMINED PIVOTAL POSITION IN REFERENCE TO SAID CLOSURE PLATE, SAID LOCKING MEANS INCLUDING A LOCKING MEMBER MOVABLY SUPPORTED BY SAID CLOSURE PLATE AND A RECEIVING MEANS ON SAID SECOND MOUNTING MEANS, AND AN ACTUATING MEMBER COACTING WITH SAID LOCKING MEMBER FOR MOVING THE LATTER INTO AND OUT OF ENGAGEMENT WITH SAID RECEIVING MEANS, SAID RECEIVING MEANS INCLUDING A LOCKING PLATE INCLUDING SEVERAL LOCKING HOLES AND SUPPORTED BY SAID SECOND MOUNTING MEANS PIVOTAL IN UNISON THEREWITH IN RESPONSE TO A PIVOTAL MOVEMENT OF THE RESPECTIVE LEVER, ENGAGEMENT OF SAID LOCKING MEMBER WITH A SELECTED ONE OF SAID HOLES LOCKING THE LEVERS IN CORRESPONDING ANGULAR POSITIONS IN REFERENCE TO THE CLOSURE PLATE. 